Cable connector



July 20, 1948; w. PETERS 2,445,533

CABLE CONNECTOR Filed July 23, 1945 INVENTOR. WALTER PETERS By d RZZ ATTORNEY,

Patented July 20, 1948 CABLE CONNECTOR Walter Peters, Linden, N. J.,assignor to The Thomas & Betts 00., Elizabeth, N. J., a corporation ofNew Jersey Application July 23, 1945, Serial No. 606,587

4 Claims. 1

This invention relates to a new and useful cable connector for securinga conductor cable in an electrical box constituting a part of theinstallation in a wiring race-way system.

More .particularly, the invention relates to a cable connector for usewith non-metallic sheathed electrical cable (or what is sometimesreferred to as unarmored cable), and the connector possesses newfeatures facilitating its installation in the knock-out openings ofelectrical boxes.

A purpose of the invention is to produce a new cable connector having astructural form and mode of operation distinguished in respect to theprior art (as represented, for example, by Church United States Patent1,644,308, issued October 4, 1927), and which retains the simplicity ofthe Church construction but overcomes the installation problems andinconveniences sometimes encountered in the field when employingconnectors of that well known form in wiring installations. The oldcable connector referred to has supplied for a long period a populardemand in building and house wiring jobs, especially where non-metallicsheathed or unarmored cable C, as shown in the Church patent, isemployed.

However, it is sometimes said to be clifiicult to insert the connectorsleeve or body 5 of the Church patent in the standard knock-out openingor hole H through which the cable C passesinto the electrical box B due,among other causes, to the necessary close fit of the round body 5 withthe box hole in order to insure permanent retention of the installedconnector in the box. In fact, the old type connector sometimes must bestruck with a hammer to force it into the box hole.

Likewise, the round body 5 of the Church connector may not readily snapor slip into the hole H of the electrical box B due to burrs orirregular and ragged portions sometimes remaining on the edge of the boxhole after knocking the usual closure plug (called the knock-out plug)therefrom preliminary to inserting the cable connector into said box;and it is this prevailing condition and lack of hole edge smoothnessWhich interposes difficulty, and indeed probably the greatest problemencountered, in producing a close-fit cable connector of the type inquestion which is readily insertable into the knock-out opening of abox.

And in addition to the foregoing problems, the adapter or cable-clampingsaddle M of the Church patent may at times lack operatively guidedsliding retention within the sleeve body 5, thlls causing misoperationor evenbecoming loosened or displaced from the body which may lead toinconvenience to the wiring mechanic when he has to readjust theclamping saddle in the body.

The foregoing are considered the more important problems which that wellknown type of cable connector presents, and which are sought to beovercome by the present invention without sacrificing the advantages ofthe old connector, to which brief reference is made above. And infinally attaining the present solution of the problems, one of the majorfactors involved is to retain the structure of the Church connector whenreforming it to make for simplicity and convenience in its installation.

Accordingly, an important purpose of the present invention, if indeednot the most important one, is to produce a cable connector possessingthe necessary close fit with a box hole which can be more readily andconveniently inserted therein by a wiring mechanic, without having toforce or hammer the connector into place, particularly where the edge ofthe box hole may be uneven, irregular, or have burrs left thereon (afterthe knock-out plug is struck from the box) which ordinarily interferewith inserting a close-fit connector in the knock-out hole, but which isnow overcome with the new type of close-fit connector herein described.

The foregoing important purpose of the invention is attained byproducing a rolled-up longitudinally split ring body having a majordiameter thereof made on the same diameter as the box hole forestablishing a close fit therewith, and also made with a segmentalportion having a smaller diameter or dimension which is somewhat lessthan the major diameter, thus rollingup or forming this newly shapedconnector body from two centers, hence out-ofround, and thus providing abody which (when compressed by hand to install it in a box hole)momentarily becomes round by reduction of its over-all size to the minordimension or diameter; and since the latter diameter is somewhat lessthan that of the box hole H, it follows that this new cable connectorvery easily slips into place and then expands to normal out-of-roundshape and boxhole size for latching therein with a tight and close fit.

Another purpose is to provide a cable connector having a new structuralform of cable-clamping saddle which positively is movably retained inoperating relation with the connector body without likelihood ofbecoming displaced from its normal operating position.

This description and the accompanying drawings explain the invention andsuggest further purposes thereof, present it in a manner preferred atthis time, demonstrate the features thereof in order to disclose thescope and principles of the invention, thus suggesting further examplesthereof which may develop out of the teachings herein or occur to otherswho may avail themselves of the benefitsof the invention, and also aidin understanding the problems sought to be solved.

Figs. 1 and 2 are to be considered together in connection withexplaining the dual diameter features of the cable connector. Both areend views of the body part alone and include a diagrammatic showing (bythe use of comparison pointer lines) of the two different sizes of whichthe connector is capable of assuming.

Fig. 1 shows the out-of-round connector body at its normal size-beforeand after inserting it in a box hole.

Fig. 2 shows the connector body momentarily compressed by which itsubstantially, throughout is rolled-up circular form, uniformly takes ona smaller diameter at the moment a wiring mechanic presses it by hand toinsert it in the box hole.

Fig. 3 is a group of views showing the dualdiameter ring body (readingfrom the left) in side, bottom and top elevations.

Fig. 4 is also a group of views showing a new form of cable clampingsaddle-side, bottom and top elevations-which is operatively carried bythe out-of-round connector body in a new manner as distingushed from theprior art heretofore mentioned.

Fig. 5 shows elevational views of the assembled cable connectorcomprising its three parts, namely, a ring body, a cable-clampingsaddle, and an operating screw. Noting from left to right, there isshown the end, side, bottom and top views of the complete connector.

Fig. 6 shows a section on the line 66 of Fig. 7, the new cable connectorin question being mounted in a knock-out box hole and gripping a, cabletherein, the ragged b urred edge being shown at the left in elevationwhere the knock-out plug has been removed, and at the right in sectionwhere the connector is shown installed with a cable. And. Fig. '7 showsa sectional view made on the line !--1. These two views, when read inconnection with Figs. 1 and 2, demonstrate the dual-diameter cableconnector in relation to a standard type of electrical box having roundknock-out holes.

Fig. 8 is a fragmentary, outside, elevational view of a conventionalelectrical box long in use and shows only that portion thereof whichrelates to the knock-out opening. The knock-out plug is shown in placein this view, whereas Fig. 6 shows that the plug has been knocked fromboth box openings shown,

Referring further to the drawing, and in order to more fully understandthe new close-fit connector herein and its mode of operation, notice isfirst taken of a standard or conventional electrical box B (Figs. 6, 7and 8). Incidentally, in the manufacture thereof, a knock-out plug P(Fig. 8) usually is punch-depressed or defined in circular form by amachin punch Which does not strike through the box wall. This leaves apartial punch cut, in the form of a hole circle HC, defined inwardly ofthe walL-with the plug P left hanging or remaining in place, to presenta solid box wall, due to the partial cut HC which re forming pressure ofthe punch which depresses this area of metal. Thus, the plug P retains asubstantial hold in the box wall pro-formed circle I-IC by reason of.not being punched fully through, plusv the grip of the weakened ear Eremaining' in part integral with the plug.

As well known, the plug P readily responds to I the tap of a hammer andimmediately frees itself from the box hole circle HC (Fig. 8) to providea hole H (Figs. 6 and 7) when the mechanic is ready to make one or moreof these knock-out openings available for the reception of one or moreelectrical cables C (Figs. 6 and 7). The several other knock-out plugsP(not shown) in the box, which may not be required in the wiringinstallation, remain intact to form a solid box wall enclosure.

In knocking the plug P from the box B, the previously weakened ear Eusually forms a jagged, burred and roughened edge R (Figs. 6 and 7)which more particularly spoils an otherwise smooth and clean box hole H.Thus the true circle of the box hole is frequently interrupted by theinwardly projecting ragged burr R formed by bendingand rupturing the earE when forcing the earto let go by hammering on the plug P to knock itout. It is the lack of smoothness around the edge of the box hole H(more pronounced at R) which causes inconvenience when installing theold type of close-fit cable connectors of the prior art.

Having in mind th foregoing conditions encountered with electrical boxesin general, when installing the electrical cable C therein with thistype of close-fit connector, it is thought that the ensuing descriptionof the cable connector, and its combination with a box,- will be morereadily appreciated, especiallyin the new connector herein which notonly is the same size as the box hole H but also is smaller than the boxhole (at the moment of entry) and characteristically bridges over therough edge R without interferonce from the latter.

The body of the new connector is shown at it, in the form of a ring orring-like body, which may be made from a sheet metal strip wrapped orrolled up to non-circular form in order to produce a connector bodyhaving its greater segmental portion formed on one diameter and asmaller segmental portion defined by another diameter. 'Ends H of thebody strip come together in spaced relation to provide a longitudinalslit at 12 to render the body It) resilient in order that it maycontract and expand,

one end H of the ring body it includes a tongue is which laps across theslit l2 and extends into a cut-out M of the other end H of the wrappedupbody. Clearance exists between the tongue l3 and cut out M in order thatno friction or rubbing may occur between the tongue and cut-out, thusmaking for freedom during the contracting and expanding motion of thering body iii. The tongue 13 and cut-out M are symmetrical, and togetherthey impart a serpentine configuration ofconvoluted form to thelongitudinal slit l2.

The two free ends II of the circular body It comprise segmental portions(shown herein as being about one-quarter of the circle) which aretrained or depressed inwardly toward the center of the body and may beon a radius slightly less than the radius of the remaining three-quartercircular portion of said body. These two segmental free end portions IIand II are formed, as for example, on what may be said to be the bottomside of the body Hi. In this way, the segmental ring end portions 1 l,which are curved inwardly, form a shorter or minor dimension across thebody (for one-quarter of the circle) than the actual diameter of theremaining (three-quarter) circular portion thereof.

Noting Fig. 1, it will be seen that an arrow IGH measures (between twoparallel pointer lines tangent to the body I!) at its diametricallyopposite sides) the outside major diameter on which the greatersegmental portion of the body is formed; and this dimension IBH is thesame diameter as the box hole II. On the other hand, an arrow l1(between its pointer lines) measures the minor dimension or lesserdiameter of the body l due to the formation of the ends I I being bentinwardly to the slight degree shown. It is the outside major diameterIGH, for three-quarters of the body circle in, which makes a tight fitin the box hole I-I; while it is the minor outside diameter l1,providing eccentricity of the body ends II, which provides for simpleand easy insertion of the body into said box hole.

Thus the major diameter IGH of the connector body i0 is greater than theminor dimension H, the difference between the two being equal to theamount at which the eccentrically disposed end segments ll, forming theslit 12, are curved inwardly out of a true circle (indicated by dotdasharc I8H) to which otherwise the body I would conform, as in the priorart represented by the Church patent. Such difference between said twodiameters 161-1 and I! is shown (Fig. 1) by the two parallel pointerlines l9, where the lower line I9 is tangent to the major diameter(dot-dash arc ISI-I), while the upper line i9 is tangent to the minordiameter l'i established by the inwardly curved free end segments H. Thedot-dash arc IBH is a continuation of the major diameter iGI-I of theconnector body it! and is the same diameter as a standard size box hole(as at H in Figs. 6 and '7, at EC in Fig. 8, and lBH in Fig. 1).

Incidentally, the related reference characters HC, H, NEH and l8I-I allshow the diameter of the box hole and also the outside major diameter(three-quarter portion) of the body ID in connection with explaining thedual-size feature of this new cable connector. It will also be notedthat the inwardly curved segmental body portions ll (which are eccentricto the body circle iii) are equally and symmetrically formed anddisposed at each side of the longitudinal serpentine slit ll? of thebody it, the slit l2 being interrupted or bridged across by the lap ofthe interfitting tongue and cut-out means l3, l4.

According to the foregoing, a wiring mechanic may easily depress thering body ill by pinching it between his fingers in the directionindicated by the major diameter arrow IBH causing said major diameter todecrease and approach toward or attain a dimension equal orapproximately so to the minor or shorter dimension H. In that way, thegeneral overall diameter of the ring body I!) is substantially reduced(see Fig. 2). It is this latter feature which makes it very simple andeasy to insert the connector body it in the standard box knock-out holeH in accordance with this invention, despite any unevenness orirregularity left in the box hole H, whether caused by a poor andinadequately clean breakaway of the knock-out plug P from the holecircle H0, or whether caused by an abnormal inwardly projecting raggedear edge E, or by both such conditions.

Coming now to Fig. 2, it is presented as a companion view to Fig. 1 anddemonstrates (a) the reduction in size of the connector body l0heretofore explained, and (1)) how it takes on a round formation indoing so. The major diameter pointer lines ltH (Fig. 1) are shownextended to embrace the pinched or reduced body Ill diagrammed in Fig.2, and are there shown at l6a. It will be seen that the major diameterindicating lines IBH and lBa are no longer tangent to the reduced circleof the connector body It) in Fig. 2. This is due to the fact that theout-of-round body it! of normal box-hole size I8H in Fig. 1 now has beencompressed and has attained a circular or round formation in Fi 2.

Accordingly, the wiring mechanic has compressed or pinched the connectorbody III (at Fig. 2) and closed the slit at I2 by bringing the ends lltogether. This general reduction in diameter occurs fairly uniformly inthe majordiameter body portion, not in the off-circle ends I l, inconsequence of which said major diameter three-quarter portion reducesto a radius comparable to the slightly shorter radius of the segmentalone-quarter end portions H. The result is that the entire body I0, IIassumes a new radius, more nearly the shorter radius of the end portionsH, by symmetrically reforming itself to a more or less true circle, asin Fig. 2.

It follows therefore that the connector body Ill, when compressed fromFig. l to Fig. 2 form, becomes circular-and significantly it then isless than the diameter [8H (also I8I-I) of the box hole H. For thisreason, the close-fitting body In, although the same size as the boxhole H (and therefore ordinarily difiicult to insert), is neverthelessnow easily and readily fitted into the box hole. It is then releasedfrom between the mechanics fingers and instantly expands, due to itsresilience, into place in and against the box hole edge H. This will bemore readily understood from the description to follow of the latchinggrooves in the body l0 and other features to complete the connector.

Having diagrammed (Figs. 1 and 2) certain of the principles involved,reference is now made to other views in the drawings. A latching groove'22 is formed annularly in each end of the connector body Ill to engagethe box hole edge H. Since the bottom of the annular groove 22 is thesame diameter as the box hole I-I, it follows that the outer tip edge orrim 23 of the groove is the same diameter as the central portion of thebody and actually of greater diameter than the box hole. Consequently,the reduction in size, from Fig. 1 to Fig. 2 is for the purpose ofdecreasing the size of the body groove rim 23 to enable it to passthrough the box hole H in order that the smaller groove 22 may expandand latch into the box hole (see Fig. 6).

Next, the body I0 is provided with a threaded screw hole 24 centrallythereof and opposite the longitudinal slit l2; and an operating screw 25(Figs. 4 and 6) it mounted in this hole. The screw length is sufficientto place its inner end somewhat beyond the axis or center of theconnector in the event the screw is run inwardly to its limit, although:when installed (Figs. 6 and 7) thisylimit is not reached due to thepresence of thecable C.

Finally, the connector bodylli has a guide slot 26 formedin each endthereof and in opposite relation to the slit l2. The. depth of thisguide slot is about equal to the thickness of the sheet metal ormaterial of a cable-clamping saddle hereinafter explained, and also thereach or segmental length of the slot 26 conforms to a counter-portionof the saddle which rides in said slot, as will be explained. There isone particular point involved, and that is to the efiect that the reachor segmental length of this saddle guideway slot 26, for the best modeof operation, preferably is at least equal to or greater than the radiusof the box hole H. In other words, the arcuate or segmental length, asmeasured laterally between the two spaced shoulder notches 26 definingsaid guideway, is shown to be somewhat greater than the radius of theconnector body Ill. The reason for this substantial or maximum width ofthe guide slot 26 is better explained in connection with thecable-clamping means or saddle, as next assembled with the connectorbody I 0.

According to the foregoing, a one-piece cableclamping saddle (of generalU-shape form when viewed in side elevation) has a pressure seat 21. Thisseat is formed and carried integrally between the lower edges of spacedparallel shutterlike end plates, each of which is depressed to provide aweb in the form of a rib 28, and including a flange 29at each side ofeach rib. The rib 28 is depressed centrally between the two side flanges29 and together .constitute the end plate. Thus it is seen that an endplate 28, 29 is provided at each extremity of the saddle pressure seat2?. This pressure seat is arched to clamp against the oval or roundingsurface of the cable (Figs. Sand 7).

The two shutter end plates 28, 29 form a sector greater than 180 degreesand act to close that portion of the connector body Ill not occupied bythe cable C. The sectoral form of the end plates is generated from aradius which locates the perimetric edge of the shutter-like end plateabout half way the thickness of the metal, forming the three-quartermajor diameter body portion It], as observed at the left-hand view ofFig. 5 showing the end of the assembled connector. There, it is seenthat the shutter 28 is in its down position, concentric with the bodyl0, and that the sectoral edge of the shutter is located midway of thethickness of the body when it is expanded to normal size. Thus. theradius of the sectoral shutter-end plates '28 is purposely smaller thanthe radius of the box hole H in order that they may readily passthrough, as shown in Figs. 6 and'Z.

"The clamping saddle pressure seat 27 is operativelyrnounted within theconnector body I0, parallel to the axis thereof, and this positionplaces the two end plates 28, 29 at each extremity of the body and atright angles to its axis. The two end-plate ribs 28 are formed in widthfor a close sliding fit with the guideway 26 at each end of theconnector body. Thus the clamping saddle 2'! is slldably carried in andon the body In and is adapted to beoperated under the pressure of thescrew 25.

The guideways 26 are die-cut to an exact and accurately predeterminedsize and spacing in order to attain a constantly. uniform dimensionbetween said two guideways, one in each end of he connector body 88.Such method of die form- 'cable'C inserted under the saddle.

ing the bodies, with die-cut guideways 26, affords a uniform fit of theclamping saddles therein for mass machine production of the connectors.Thus the variation of a few thousandths of an inch, which exists in thecommercial width of the stock strip metal from which the bodies Ill aremade and which causes the overall length of the bodies to vary in themass production thereof, does not mitigate against the uniformity of fitb tween the bodies and clamping saddles in the course of manufacturin inquantity.

In other words, the die-formed clamping saddles themselves are exact anduniform in their dimensions, as between the spaced rib end plates 28,but the stock strip metal for producing the bodies it is not of uniformwidth. The latter difficulty is overcome by die-cutting the two spacedguideway slots 2'6 to exact dimension (irrespective of the variation inwidth of the body stock strip), to receive and establish an operatingfit with the ribs 28 of the saddles. Consequently the side flanges 29are not depended upon for an operating or sliding fit with the bodieswhich vary in length, and this is an important manufacturing advantage.

Next to be understood is that by providing a wide slot forming theguideway 26, it follows that the shoulders 26 defining the guideway arelocated substantially down on each side of the body I 3 and away from amedial center line passing through the guideway. This means that theslidable ribs 28 constitute the greater area of the shutter-end plates.The wide slot 26 and its correspondingly wide rib 28 slidable thereinare both designed and constructed for the purpose of maintaining theclamping saddle 27 in operative and sliding engagement for all itspositions within the connector body Hi. It is found that this feature ofmaximum 'width minimizes the likelihood of the slidable cable-clampingsaddle from dropping out of place when it is down to the limit as shown.in the left-hand View of Fig. 5.

Accordingly, the wider or longer the arcuate reach of the slot 26, andthe wider the cooperating rib 28, the greater is the guided retentionthus provided for the clamping saddle 2'. in and upon the connector bodyit). One relationship found to be efficient in this connection is tomake the arcuate reach of the slot 25, that is, the distance between theslot shoulders 26, and hence the width of the rib 253, a little greaterthan (or comparable to) the radius of the connector body ID at its fullnormal size. This relationship is shown in the drawings in connectionwith demonstrating the principle involved and the commercial form ofmanufacture.

The foregoing maximum width of the shutter rib 28 and the widely spacedguideway shoulders 26 prevents the shutter rib from coming out of placefrom the body It when handling the connector preliminary to inserting itin the electrical box 13. Furthermore, it is found that this maximumwidth guiding feature renders possible a minimum size for the shutterends, and makes practical the manufacture thereof in size, relatively tothe body it, as shown in the left-hand view of Fig. 5.

Coming next to the use of the cable connector, its installation in anelectrical box B is shown in Figs. 6 and 7. Either grooved end 22 of theconnector is inserted in the box hole H (the simplicity of which waspreviously explained), the clamping saddle 2? then lifted upwardly, andthe The screw 25 then is tightened down to grip the cable C between thesaddle and the bottom inside of the connector body. The pressure of thescrew 25 causes the body 9 to expand (note the spread of the slit i2 inFig. 7) to the limit of the box hole H and permanently locks it Withinthe boX. This is accomplished by virtue of the expanded pressureengagement of the three-quarter major diameter portion of the body [9against the box hole edge. Incidentally, the sectoral shape of the endshutters 528 maintains closed the open ends of the body 6 for all sizesof cable which the connector is adapted to receive.

In addition to the foregoing, one of the more important features of theconnector, and its new mode of use with the conventional box, will now,

be explained. When the connector is to be inserted, the mechanic havingmomentarily compressed it (Fig. 2) to the round form smaller than thebox hole H, he then simply lines up or matches the bottom slit H withthe burred edge R of the box hole and inserts the connector. Thisselected position of the connector in the box is shown in Figs. 6 and 7,where the eccentric segmental ends ll of the body are shown spacedabove, that is, in alignment with, and in clearance relation to, theragged or burred edge R of the box hole. Consequently the eccentricityof the connector portion 1 I prevents it from impinging the ragged edgeR and causes it to bridge over and easily slip into the box hole H.

Now will be seen a further advantage of devising the eccentric body endsit in combination with the serpentine slit l2, l3, Hi. This arrangementsupports the cable C well above the burred edge R (Figs. 6 and 7) of thebox knock-out opening H and provides such adequate clearance between thecable and box hole as to insure against contact of the cable with thebox hole edge in the event the cable should squeeze down into the slitI2.

According to all the foregoing, it will be seen (a) that momentarilycompressing the connector reduces its size (Fig. 2) to a diameter lessthan that of the box hole H and therefore any lack of a clean break-awayof the knock-out plug P from its hole circle I-IC does not interferewith inserting the connector; also (b) it will be appreciated that theeccentricity at H of the body provides for easy slip-in of the connectordespite the presence of burrs R left by the plug P when broken away fromits retaining ear E; and (c) that this new cable connector possesses atight fit and close relationship with the box hole.

The disclosure herein explains the principle of the invention andpresents the best mode contemplated in applying such principle, so as todistinguish the invention from others; and there is particularly pointedout and claimed, the part, improvement or combination, Which constitutesthe invention or discovery, as understood by a comparison thereof withthe prior art.

This invention is presented to fill the need for a useful cableconnector. Various modifications in construction, mode of operation, useand method, may and often do occur to others skilled in the art,especially so after acquaintance with an invention. Accordingly, thisdisclosure is exemplary of the principles and equivalents without beinglimited to the present showing of the invention.

What is claimed is:

1. A cable connector comprising a ring-like body having an annulargroove and a longitudinal slit, and having the major portion of itsring-like body formed on a diameter adapted to be received into theknock-out hole of a box, the end portions of the body adjacent thelongitudinal slit being depressed inwardly of said diameter, therebyadapting said end portions to have clearance relation with a ragged anduneven edge portion of the box hole, and an operating screw mounted inthe body for clamping a cable inserted therein and expanding the annulargroove into anchored engagement with the edge of the box hole.

2. A cable connector comprising a ring-like body having an annulargroove and a longitudinal slit, and being formed out-of-round byrollingup a portion thereof on a major diameter and the remainingportion on a minor diameter, thus forming a body capable of beingcontracted by inward pressure to a size substantially equal to a ringhaving said minor diameter, and operating means carried by the ring-likebody for clamping a cable inserted therein and expanding the annulargroove into anchored engagement with the edge of a box hole.

3. A cable connector comprising a ring body with end grooves and alongitudinal slit, and being formed out-of-round by rolling-up more thandegrees of the body on a major radius and less than 180 degrees of thebody on a minor radius, thus forming a dual-diameter body, whereby theconnector may be compressed to reduce its size to approximately itsminor radius, and operating means carried by the body to expand and lockit in an electrical box hole into which the cable connector is adaptedto be mounted.

4. A cable connector comprising a rolled-up body having a longitudinalslit adapting said body to contract and expand, a guideway slot providedat each end of the body opposite the slit, the guideway slots beingformed by spaced shoulders die-cut into the body ends, said shouldersbeing spaced apart a distance at least as great as the radius of thebody thus providing a substantially wide guideway; a clamping saddlehaving a pressure seat disposed within the body, and having ashutter-end plate of sectoral form carried at each end of the pressureseat, with a rib depressed inwardly of each shutter-end plate and of awidth also at least as great as the radius of the body, said ribs beingslidably mounted within the wide guideways of the body; and an operatingscrew mounted in the body opposite the slit and effective against theclamping saddle to force the pressure seat toward the slit.

WALTER PETERS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,644,296 Thomas Oct. 4, 19271,734,202 Church Nov. 5, 1929 1,787,668 Church Jan. 6, 1931 1,793,883Church Feb. 24, 1931 1,816,667 Church July 28, 1931 1,816,668 ChurchJuly 28, 1931 1,833,988 Church Dec. 1, 1931 1,938,974 Oldberg Apr. 10,1933

